Cylindrical articles and method and apparatus for manufacturing the same



y 1935- G. E. LANDT 2,001,031

CYLINDRIGAL ARTICLE AND METHOD AND APPARATUS FOR MANUFACTURING THE SAME Filed Feb. 4, 1932 a ZZ Patented May 14, 1935 CYLINDBIGAL ARTICLES Ann METHOD AND APPARATUS FOR MANUFACTURING THE SADIE Gustave E. Landt, Norrlstown, Pa, assignor to Continental-Diamond Fibre Company, Newark, Del., a corporation of Delaware Application February 4, 1932, Serial No. 590,964

3Claims.

obtained; and to methods and apparatus for manufacturing such articles. While the invention is applicable to articles of any length, it is particularly adapted to the manufacture of relatively long tubes and rods, since it is possible by my process to employ two or more fibrous sheets in side by. side relation, in contradistinction to methods heretofore employed where the length of the article has been limited by the width of the fibrous sheet material employed in its manufacture. Although attempts have been made to manufacture tubes and rods comprising two or more fibrous sheets positioned side by side, such tubing has not been satisfactory, due to the unsatisfactory joint between the two fibrous sheets. The present invention enables the production of articles of any desired length, having great strength and homogeneity of structure.

The principal object of my invention is to provide improved cylindrical articles, such as tubes and rods, of the type specified and to provide an expeditious method of making such articles.

Another object of my invention is to provide a novel machine for carrying out the contemplated method for manufacturing articles having the desired construction.

Other objects will be apparent from a considerationof the specification and claims.

The method contemplated by the invention comprises broadly the provision of complementary interdentate edges on a plurality of fibrous sheets, positioning the sheets side by side with the said edges in cooperative relation, and winding the sheets upon a mandrel. While the invention is not limited to the specific method disclosed herein, I prefer to practice it in the manner illustrated and described. In such case, the

sheets are placed side by side with the edge portions of the adjacent sheets overlapping, the

overlapped portions are cut so as to form complementary interdentate or interlocking edges on adjacent sheets, the waste material cut from the sheets is removed, and the sheets are wound to form the cylindrical article. The cutting of the sheets is performed in such manner as to provide junctures of the adjacent sheets comprising non-rectilinear complementary edges of the sheets of fibrous material, and the design of the cut is so chosen relative to the diameter of the article desired that, in any particular instance, the junctures weave back and forth on the completed article, and the junctures in any one layer are non-coincident with the junctures of the sheets in at least certain of the layers.

The apparatus contemplated by the invention comprises means for performing each of the essential steps of the method when practiced in the broad sense indicated above. Although I disclose herein and prefer to use apparatus for performing the method in the specific manner stated above, it is to be understood that the invention is not thus limited.

I have chosen to illustrate the invention here-- in as applied to the manufacture of tubes, but it will be understood, of course, that it is not thus limited, and is applicable to the manufacture of cylindrical articlesgenerally, such for example as rods with or without a central core.

A complete disclosure of the construction of an improved tube, a novel method of making the same, and a novel apparatus for performing the method is contained in the following detailed description and the accompanying drawing.

In the drawing:

Figure 1 is a diagrammatic elevational view illustrating in a general way an apparatus for making the tube, and for employing the method involved;

Figure 2 is a face view of two adjacent sheets illustrating clearly the manner in which such sheets are positioned and cut in carrying out the method of the invention as disclosed herein;

Figure 3 is a perspective view of a partially wound tube showing clearly the interlocking relationjof the sheets, and having a part of one sheet broken away to show the non-coincidence of the sheet junctures in superposed layers or wrappings; and

Figure 4 is a front elevational view of the cutting assembly which forms a part of the tube making apparatus.

The fibrous sheet material may be wood pulp, cotton rag, asbestos or other paper; or it may be cloth. The fibrous sheet material is preferably coated or impregnated throughout its entire surface with an adhesive or binder prior to the winding on the mandrel, although in some instances it will be sufiicient to apply the adhesive to portions of the fibrous sheet material adjacent the edges of the individual sheets. In cases where mechanical strength is not a factor, tubes may be made in which any suitable fastening means, such as an adhesive, is associated with the innermost and outermost layers only to prevent the unwinding of the finished tube. Any suitable adhesive may be employed, for example, glue;

shellac, or other natural resins; latex; or any one of the so-called synthetic resins. In the preferred form, a synthetic resin of the phenolic type is employed, which, as is well known, exists in two stages, to-wit, the initial or soluble and fusible stage, and the final or insoluble and infusible stage, the latter resulting from heating the initial resin with or without pressure.

The adhesive may be applied to the fibrous sheet material prior to the formation of the interdentate edges, or it may be applied thereafter. Since the binder must function at the time the fibrous sheets are wound on the mandrel, the particular time of application of the adhesive to the fibrous sheet material will depend to some extent upon the nature of the adhesive. In the use of the phenolic resins, of which the phenolformaldehyde resin is typical, resin-impregnated paper may be employed. This paper may be prepared in accordance with the usual method of immersing the paper in an organic solvent solution of the synthetic resin in its initial stage with the subsequent evaporation of the solvent. If the resin-impregnated paper is employed, a hot plate is provided, over which the paper is passed prior to the winding on the mandrel. The function of the hot plate is to melt the synthetic resin which furnishes a suflicient adhesion to join firmly the sheets together as they are wound on the mandrel. In an optional method employing a phenolic resin as the binder, the edges of the sheets may be cut as described, and thereafter the sheets may be passed over the hot plate upon which powdered resin in its initial stage is fed. The hot plate maintained, for example, from degrees C. to degrees C. causes the resin to melt and the paper is thus impregnated with the resin. The paper may then be passed under the mandrel upon which it is to be wound and the pool of liquefied resin collecting on the paper between the supporting roll and the mandrel aids in the impregnation of the paper.

In case phenolic resin or other heat-convertible material is employed as the binder, the tube, after it is wound, may be subjected to heat, either with or without pressure to convert the binder into the second infusible, insoluble stage,

for example, in tubes manufactured with phenolformaldehyde resin as a binder, they may be placed in a heater at degrees C. to 230 degrees C. for approximately six hours, at the end of which time the binder will be converted into the final stage.

The edges of the adjacent sheets of fibrous material may be cut by hand, or by any machine adapted for the purpose. The form of the cut may be varied widely, for example, it may be un dulate, or zig-zag, or any other form, provided that the straight-line edges are destroyed and the non-rectilinear lines of one sheet are complementary to the non-rectilinear lines of the adjacent sheet, that is to say, there will be no substantial overlap of the sheets, and no substantial gap or opening between the sheets. The out also preferably bears such a relation to the diameter of the tube desired that the line of juncture in any given layer of the fibrous material will not be coincident with the line of juncture of the sheets in the adjacent layers. These interdentate edges form a joint which is as strong as the sheet material from which the tube is made. The tubes also contain the same number of laminations throughout, and are homogeneous in structure.

In the accompanying drawing there is' shown a method and apparatus for forming the tube 0 the invention. Referring to Figure 1 of the drawing. there is shown a pair of take-oi! rolls I and 2 having the fibrous sheets wound thereon. which rolls are positioned so that adjacent edges of the fibrous sheets overlap only to a desired predetermined extent. For the purpose of illustration, the method of making my novel tube is illustrated herein as applied to two adjacent sheets only, but it will be understood that any desired length of tube may be made by positioning the required number of sheets in a row with adjacent edges overlapping. If three or more sheets are used, three or more rolls, similar to rolls i and 2, will be positioned in the specified manner. When resin-impregnated paper is used, as previously mentioned, such paper impregnated with the resin in its initial stage is wound in sheet form upon the take-off rolls. The two sheets are simultaneously unwound from the take-oil rolls and pass as a continuous web designated by the reference character 3 through a cutting device 4 (described in detail hereinafter) and over a heating plate 5 and around a mandrel S which is positioned upon rotatable rolls 7. If desired, an adjustable pressure roll 8 may be used to insure tight winding of the tube. However, in general sufficient tension is obtained in the fibrous web without the use of such pressure roll. The mandrel 5 may be driven, by any suitable source of power and rolls i may be used merely as supports for the tubes.

The manner in which two adjacent sheets are positioned relative to each other and the manner in which they are cut by the cutting device is illustrated more clearly in Fig. 2, wherein the overlapping edges are shown at E. Preferably the cutting element moves back and forth in a direction substantially perpendicular or transverse to that of movement of the sheets and as a result a sinusoidal cut I0 is made along the edges of both overlapping sheets simultaneously. The cutting element is preferably made to move over practically the entire width of the overlapping sheet portions so that separable waste pieces or strips ii and ii. are cut from the respective sheets. When these waste pieces are removed, the edges of the sheets abut in interlocking or interdentate relationship as illustrated in Fig. 3. Waste strips Ii and i2 may be drawn away from the sheets as indicated in Fig. 1 by any suitable means (not shown), such as take-oil or draw rolls. Alternately, the cut may be made .to extend over the entire width of the overlapp g sheet portions; in which case instead of was e strips, there will be small waste pieces which may be blown or picked oi! the web in any suitable manner.

Following the above described cutting operation, the web is passed over the heating plate 5 which not only serves to support the web, but also heats the resin and causes it to melt. The impregnated sheet web is then passed under and around mandrel 6 upon which it is tightly wound.

Referring to Fig. 4, there is illustrated in this figure the desired form of cutting assembly which is utilized to cut the overlapping sheets as de scribed above. This assembly comprises a frame I! which is adapted to oscillate longitudinally by any suitable means which provides the desired slotted supporting plates l9, respectively. The web of adjacent sheets is passed over plates II and between bars I6 and ll of the frame. The frame may be of any desired length to accommodate any length of tube 'and as many supporting and cutting elements as are necessary may be provided on the frame. The frame terminates at its ends in shafts 25 and 26 which are slidably mounted. in bearing standards 21 and 28 respectively.

Each of the cutting elements comprises a knife blade 20 mounted on a support 2 I. The support ii is pivotally attached as at 22 to the supporting arm 23 depending from bar IS in order to allow the knife blade 20 to align itself with the direction of cut and thus prevent tearing of the sheets. The knife blade 20 extends into the arcuate slot 24 of plate I9 and the slot allows the blade to pivot freely on its support. In operation, the web passes over the supporting plate, as before stated, and the oscillating knife makes the desired cut in the overlapping sheet portion.

Tubing manufactured in accordance with the present invention has all the characteristics of tubing made from a continuous sheet of fibrous material, since the junctures of the sheet weave back and forth, and are so arranged .with respect to the diameter of the tube that the lines of juncture are never coincident in adjacent layers. In this manner, a localized joint structure is provided having numerous non-coincident interlocking intermeshing points throughout the same, which imparts to.the article the strength of a seamless article. The length of tubing which may be manufactured is limited only by the size of the machine for making it, and the number of rolls of fibrous material which can be utilized with the machine. The improved tube, particularly when a phenolic type of binder is employed, is mechanically strong, and has high electrical insulating properties. Furthermore, the, walls of the tubes of the present invention are uniform in thickness throughout the length of the tubes, in contradistinction to the attempts which have previously been made to manufacture tubes from a plurality of sheets, which resulted in tubes lacking in homogeneity.

While I have disclosed herein a preferred embodiment of the method and apparatus for constructing the tubing, various modifications and changes in this method, as well as in the apparatus are possible within the scope of the invention. The appended claims define the invention, and any modifications which come within the scope thereof are deemed to be a part of the invention.

Iclaim: l. A method of making a cylindrical artic from fibrous sheet material and a resinous binder, which comprises feeding adjacently disposed sheets with overlapping longitudinal edges, cutting the sheets at their overlapped portions as they are being fed in a manner to form complementary interdentate edges on the sheets, and so that the junctures of the sheets in the successively wound layers are non-coincident but are superposed one above another, whereby a localized joint structure having numerous non-coincident interlocking intermeshing points throughout the same is provided.

2. In a machine for making cylindrical articles from fibrous sheets, means for winding the sheets spirally to cylindrical form, means for feeding adiacently disposed sheets with overlapping longitudinal edges toward said winding means, and means for simultaneously cutting the sheets at their overlapped portions as they move toward said winding means in a manner to form complementary interdentate edges on the sheets immediately prior to the winding thereof.

3. A cylindrical article, comprising a single spirally wound composite sheet composed of adjacent sections having complementary interdentate edges and united by a synthetic resin, said sheet being wound so that the lines of juncture of said. sections in the successively wound layers are non-coincident and cross each other, whereby there is provided a localized joint having numerous non-coincident interlocking intermeshing points.

GUSTAVE E. LANDT. 

